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Light therapy is certainly having a surge in popularity. Consumers can purchase illuminated devices targeting issues like skin conditions and wrinkles as well as aching tissues and oral inflammation, the latest being a toothbrush enhanced with small red light diodes, described by its makers as “a major advance in at-home oral care.” Globally, the industry reached $1 billion in 2024 and is forecast to expand to $1.8 billion by 2035. You can even go and sit in an infrared sauna, where instead of hot coals (real or electric) heating the air, the infrared radiation heats your body itself. As claimed by enthusiasts, the experience resembles using an LED facial mask, boosting skin collagen, soothing sore muscles, relieving inflammation and long-term ailments and potentially guarding against cognitive decline.

Understanding the Evidence

“It feels almost magical,” notes a neuroscience expert, professor in neuroscience at Durham University and a convert to the value of light therapy. Of course, certain impacts of light on human physiology are proven. Sunlight enables vitamin D production, needed for bone health, immunity, muscles and more. Light exposure controls our sleep-wake cycles, as well, triggering the release of neurochemicals and hormones while we are awake, and winding down bodily functions for sleep as it fades into night. Artificial sun lamps are standard treatment for winter mood disorders to boost low mood in winter. So there’s no doubt we need light energy to function well.

Different Light Modalities

While Sad lamps tend to use a mixture of light frequencies from the blue end of the spectrum, the majority of phototherapy tools use red or near-infrared wavelengths. In rigorous scientific studies, like examinations of infrared influence on cerebral tissue, finding the right frequency is key. Light is a form of electromagnetic radiation, which runs the spectrum from the lowest-energy, longest wavelengths (radio waves) to short-wavelength gamma rays. Therapeutic light application uses wavelengths around the middle of this spectrum, with ultraviolet representing the higher energy invisible light, then visible light (all the colours we see in a rainbow) and then infrared (which we can see with night-vision goggles).

UV light has been used by medical dermatologists for many years to treat chronic skin conditions such as eczema, psoriasis and vitiligo. It affects cellular immune responses, “and reduces inflammatory processes,” explains a dermatology expert. “Considerable data validates phototherapy.” UVA reaches deeper skin layers compared to UVB, whereas the LEDs we see on consumer light-therapy devices (typically emitting red, infrared or blue wavelengths) “generally affect surface layers.”

Safety Protocols and Medical Guidance

Potential UVB consequences, such as burning or tanning, are well known but in medical devices the light is delivered in a “narrow-band” form – meaning smaller wavelengths – that reduces potential hazards. “Therapy is overseen by qualified practitioners, meaning intensity is regulated,” explains the dermatologist. Most importantly, the devices are tuned by qualified personnel, “to guarantee appropriate wavelength emission – as opposed to commercial tanning facilities, where regulations may be lax, and emission spectra aren’t confirmed.”

Consumer Devices and Evidence Gaps

Red and blue light sources, he says, “don’t have strong medical applications, but they may help with certain conditions.” Red light devices, some suggest, improve circulatory function, oxygen utilization and skin cell regeneration, and activate collagen formation – a primary objective in youth preservation. “Research exists,” states the dermatologist. “But it’s not conclusive.” In any case, given the plethora of available tools, “we don’t know whether or not the lights emitted are reflective of the research that has been done. We don’t know the duration, how close the lights should be to the skin, if benefits outweigh potential risks. Numerous concerns persist.”

Specific Applications and Professional Perspectives

Early blue-light applications focused on skin microbes, a microbe associated with acne. Scientific backing remains inadequate for regular prescription – although, says Ho, “it’s commonly used in cosmetic clinics.” Individuals include it in their skincare practices, he says, but if they’re buying a device for home use, “we advise cautious experimentation and safety verification. Unless it’s a medical device, the regulation is a bit grey.”

Innovative Investigations and Molecular Effects

Meanwhile, in a far-flung field of pioneering medical science, scientists have been studying cerebral tissue, identifying a number of ways in which infrared can boost cellular health. “Nearly every test with precise light frequencies demonstrated advantageous outcomes,” he reports. Multiple claimed advantages have created skepticism toward light treatment – that it’s too good to be true. However, scientific investigation has altered his perspective.

Chazot mostly works on developing drug treatments for neurodegenerative diseases, but over 20 years ago, a doctor developing photonic antiviral treatment consulted his scientific background. “He created some devices so that we could work with them with cells and with fruit flies,” he recalls. “I was quite suspicious. It was an unusual wavelength of about 1070 nanometres, which most thought had no biological effect.”

Its beneficial characteristic, nevertheless, was that it travelled through water easily, enabling deeper tissue penetration.

Cellular Energy and Neurological Benefits

Additional research indicated infrared affected cellular mitochondria. Mitochondria produce ATP for cell function, creating power for cellular operations. “Every cell in your body has mitochondria, particularly in neural cells,” explains the neuroscientist, who concentrated on cerebral applications. “Studies demonstrate enhanced cerebral circulation with light treatment, which is consistently beneficial.”

With 1070 treatment, energy organelles generate minimal reactive oxygen compounds. At controlled levels these compounds, says Chazot, “triggers guardian proteins that maintain organelle health, preserve cell function and eliminate damaged proteins.”

Such mechanisms indicate hope for cognitive disorders: oxidative protection, anti-inflammatory, and pro-autophagy – autophagy being the process the cell uses to clear unwanted damaging proteins.

Current Research Status and Professional Opinions

Upon examining current studies on light therapy for dementia, he states, several hundred individuals participated in various investigations, including his own initial clinical trials in the US